A Thin Film Transistor Liquid Crystal Display (TFT-LCD) with the advantages of light weight, thinness, small occupied area, low power consumption, low radiation and the like is widely used in various data processing apparatuses, such as televisions, laptops, mobile phones, personal digital assistants, etc. With continuous development of electronic industry, the performance of the TFT-LCD is increasingly high.
A semiconductor switching device is configured in each pixel of the TFT-LCD, wherein the pixels are independent transistors isolated from one another. Because each pixel may be directly controlled through a dot pulse, each node is relatively independent and may be continuously controlled, in this way, the reaction time is shortened, and meanwhile, the gray scale control is very accurate.
Generally, a TFT includes a gate connected to a gate line, so that the TFT could be turned on and off through scan signals applied through the gate line. In addition, the TFT also includes a first electrode (for example, a source) connected to a data line and a second electrode (for example, a drain) connected to a pixel electrode. Liquid crystal molecules (or a liquid crystal layer) are arranged between the pixel electrode and a common electrode coupled to a common electrode line.
When the TFT-LCD works, the polarities of voltage differences applied to the liquid crystal molecules must be inverted at set intervals, to avoid permanent damage caused by polarization of a liquid crystal material and avoid an Image Sticking effect. Hence, various polarity inversion methods are proposed, including Frame Inversion, Line Inversion and Dot Inversion, wherein the line inversion specifically includes Row Inversion and Column Inversion. At the end of a frame write-in and before the start of the next frame write-in, if the voltage polarities in the pixels of a whole frame are the same (all positive or all negative), it is referred to as the frame inversion; if the voltage polarities in the pixels on the same column are the same and the voltage polarities in the pixels on the left and right adjacent columns are opposite, it is referred to as the column inversion; if the voltage polarities in the pixels on the same row are the same and the voltage polarities in the pixels on the upper and lower adjacent rows are opposite, it is referred to as the row inversion; and if the voltage polarity in each pixel is opposite to the voltage polarities in the upper and lower, left and right adjacent pixels, it is referred to as the dot inversion.
For the frame inversion manner, flicker will be generated as a result of nonuniform transmittance between continuous frames; and crosstalk easily occurs due to interference between adjacent data. For the row inversion manner, because the voltage differences with the same polarity are allocated to the pixels arranged horizontally, horizontal crosstalk easily occurs. For the column inversion manner, the horizontal crosstalk may be reduced, but vertical crosstalk easily appears.
Whereas for the dot inversion manner, the polarities of the voltage differences applied to adjacent pixels are mutually inverse in all directions to produce optimal image quality. However, in the dot inversion manner used at present, polarity inversion signals are generally provided by data lines, and polarity inversion is performed between pixel display dots, so the positive and negative polarity inversion signals provided by the data lines need to be frequently switched, and the display power consumption would be increased.